Screening tests are now used commonly to test compounds for potential pharmaceutical activity, and to test the environment for the presence of possibly deleterious substances. Some compounds are easily detected using standard chemical and spectroscopic techniques, while others are determined by their quick inflammatory or toxic effects on a test organism. However, there are many compounds (both potential pharmaceutical compounds and potential pollutants) that affect organisms developmentally. Developmental effects are more difficult and time-consuming to detect, as screens for such may require that one observe a test subject over the course of the organisms entire development. Bacteria, yeast, and isolated cell cultures may be poor test organisms, for failure to react and develop in a way analogous to higher animals.